Coronary artery disease affects the lives of millions of people, and may affect the health of a patient without warning. Detection of coronary artery stenosis involves patient history, physical examination, stress testing and possibly a coronary angiogram. Beyond history and physical examination, the diagnostic technique is associated with significant cost and risk. Although the stress test is the most frequently ordered test to detect possible coronary artery disease, sensitivity and specificity of the stress test vary greatly from 40 percent to 90 percent, depending upon whether there is single or multi-vessel disease.
During routine physical examination in a clinic office, physicians and other medical providers use a stethoscope. It is inexpensive, easily portable, relatively comfortable, and safe. Advancements in digital technology have led to the production of electronic stethoscopes that can amplify sound, record patient data and transmit data to a computer for further processing. The transmitted data can be used to plot a phonocardiogram, improve patient records and even perform automated heart sound diagnosis.
Within the electronic stethoscope, an acoustic sensing device is employed to transmit the raw sound data from the patient to electronics within the stethoscope. The raw data from these sensors contains a plethora of acoustic information emanating from the thorax that includes not only heart valve and lung sounds but also acoustic information within the stethoscope sampling frequency and signal to noise ratio. Once in digital form, the data from the stethoscope sensor is filtered so that it sounds like a mechanical stethoscope.